Flush or not to flush....

So a couple weeks ago i made a post about a sticky transmission.. I drive a 1991 e34 with a m50 engine.. Anyways i recently purchased the car as the body had absolutley no rust minus a bit under the fuel door.. Well because i just bought it an the auto transmission has no dipstick an it sticks when shifting between gears ( not all the time but enough to notice.. Some over reving when it does shift maybe up to 2000rpms..) I took it to a mechani who my friend is apprenticing for cause i have no lifts an he was only gonna charge me 35 dollars to lift an top it up if needed. Once he got through googling types of transmissions my car may have ( i dont know either an could use some help..) an looking at the transmission with a blank look flashing his flashlight around for about 20 minutes he popped the plug an stuck his finger in an the oil was a bit clear an he said smelled burned. He also mentioned there was metal shavings in it an the transmission was on its way out and i should consider dumping my car which he meant selling it as it would cost 5 thousand plus to do. Not to say i wanted to punch him in the throat since the car in excellent condition for its age an selling is far from my mind. I read that flushing ur transmission can rid it of all the old oil an other deposits which im thinking he mistook as metal shavings an improve performance. The engine is well kept an no leaks other than needing to replace the valve cover gasket and purrs like a kitten. So my question is do i flush it an possibly send my transmission on its way to " tranny heaven" ( it does exist.. Lol) or change filters an oil or just top up an start looking for a replacement which seems inevitable. Thanks again sorry if i was rambling.. Just so u know i took my car to a car wash after leaving that shop an washed an waxed her and told her not to listen to what that simple man was saying... And i didnt pay him a dime for sticking his finger in the fill hole... Again thank you...

Overrevving to about 3000rpms i mean not 2000rpms..

I didn't read this sadly.....but I think you want to know if you should flush your transmission.


Get a sample of your fluid somehow.
If it is full of particles and metal shavings, do not flush it.
If it looks clean and reddish, go ahead and flush it.

Yeah its burnt an i being looking online at different forums about flushing an decided im not going to pay 175 for a flush when i could use it towards a used transmission. Im lookin for a replacement transmission in the mean time. Thx

OK.

Hate to say it, but consider a 5 speeder swap too.

Transmission is toast, do not bother flushing now.

Do the 5 speed swap, the auto's for these cars blow IMO.

All transmission specialists I have spoken with over the past 25 years have always told me to NEVER flush a transmission. Speak to true transmission specialists, and they will tell you that normal maintainence would be to drop the pan and replace the filter and fluid.
Depending on your trans, you may have 1 or 2 pans. In my case on the 1994 525i there are 2 pans. Both need to be dropped and gaskets replaced, but only the big pan has the filter inside. The small pan needs to be filled with as much fluid as you can possibly handle during reassembly, and the large pan is filled thru the fill hole. After bringing the car up to operating temperature, you'd need to add likely another 20 ounces of fluid. If you do not do this second step, you will be low on fluid. As far as transmission maintainence after the fluid has not been replaced for lots of miles, I think the opinion that changing the fluid and causing problems is a lot of bunk. To me, doing a fluid change, no matter how long the old fluid has been in there, is wise. Also, I don't believe in LIFETIME trans fluid.

Originally Posted by johnniek

Also, I don't believe in LIFETIME trans fluid.

Tell that to my 250K mi. auto...

@Monsignor:

You are indeed very fortunate.

dont i know it

I was having a very similar issue with my car, 1995 525i 161k mi. It was sticking, over reving and it even cut off a few times when I came to a quick stop. Last weekend I had the fluid serviced (not flushed) and the filter and gaskets replaced now it is shifting as smooth as it was when I bought it. I think its worth a try especially if you are considering replacing the transmission like I was.

Originally Posted by Monsignor

Tell that to my 250K mi. auto...

Versus how many dead autoboxes that havent made it to half that.

Anyway what kind of "lifetime" did BMW account for when they say "lifetime"? 10 years? That recommendation sounds very much like planned obsolescence. They probably know few people hold their prestige ride for 10+ yrs so screw all us 2nd hand buyers huh.

Originally Posted by johnniek

All transmission specialists I have spoken with over the past 25 years have always told me to NEVER flush a transmission. Speak to true transmission specialists, and they will tell you that normal maintainence would be to drop the pan and replace the filter and fluid.

Whoever these guys are that you talked to... sounds to me like they are trying to drum up some business with that advice.

The manufacturers reccomend, in fact some times REQUIRE fluid exchanges on a regular basis. The "lifetime" thing was common in the late 90's but has been proven to be a really bad idea in most cases.

Just dropping the pan, changing out ~20% of the fluid and the filter is not much of a service IMO. Do you just change a couple qts of oil and the filter when you do an engine oil change?

Fluid exchanges are excellent maintenance. They will not "fix" problems after the fact which is where they get a bad rap. The term "flush" also gets manipulated into being a bad thing somehow. The notion being you are going to knock loose deposits, just more urban legend.

The best advice is to carefully inspect an old auto trans car before buying. They are quite prone to failure at high milage. I bet we see 5 posts a week on similar subjects. I personally just would not buy one of these with an automatic.

Originally Posted by Monsignor

Tell that to my 250K mi. auto...

^ + 1

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